Twin NASA spacecraft deliberately crash into moon

PASADENA, Calif. -- Two NASA spacecraft have wrapped up their mission by intentionally crashing into the moon. Engineers on Monday commanded the spacecraft to fire their engines and burn their remaining fuel.

The first slammed into a mountain near the moon's north pole. Its twin followed seconds later and aimed for the same target. Since the impact site was in darkness, NASA had said the crash wouldn't be visible from Earth.

The spacecraft named Ebb and Flow circled the moon for nearly a year, mapping the lunar gravity field.

To do their job, they had to fly at low altitudes above the surface, which consumes a lot of fuel. NASA decided to execute a controlled crash and bring the spacecraft down far away from any historical site on the moon.